Misc bug fixes, Solo Survival Arena aggro adjustment.

[skittles1]

-Fixed Bramble Wall starting hit points (were being spawned with 0HP).
-Fixed Bramble Wall damage threshold messages.
-Stop thrasher spin attacks hitting phased/spectating players.
-Fix a bug causing thrasher spin attacks to overwrite the damage to be
done to each target with the value returned from the previous target.
-Changed thrasher spin attacks to use high precision damage numbers.
-Survival arena now checks for invalid targets before calling
TargetSwitch.
-Added IsOwnedByPlayer message in Monster. Returns TRUE if the monster
(or its master) is owned by a player, FALSE otherwise. Checks for
apparitions and monster evil twins in addition to true minions.
-Added minion checks to the aggro code in survival arenas, to stop
player minions being aggroed on players.
-Fixed bug causing new mobs to not aggro properly if a boss or miniboss
is present.
-Lowered solo aggro to 20% of mobs spawned.
-When one participant is left in guild survival, or on every kill in
solo, try to aggro another mob on the player.
-Fixed grammar error (her/his vs he/she) in phased out cast resource.
-Add a check for phase/spectator to CheckPlayerAttack in Spell.
-Formatting fixes in AttackSpell (no code change).
-Add phase/spectator check for Earthquake and radius projectile
targeting.
-Add immortal and phase/spectator check to Heat's damage effect.
-Add utility message (CreateSpellBook) to create a spell book for
monsters to use. Creates a one-spell spellbook only; good for testing.
-Add stats to keep track of highest level reached in each of the arenas.
-Add system message to get survival status report easier.
-Fix karma change in survival arena.